chromium/views/controls/single_split_view.h

// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef VIEWS_CONTROLS_SINGLE_SPLIT_VIEW_H_
#define VIEWS_CONTROLS_SINGLE_SPLIT_VIEW_H_

#include "views/view.h"

namespace views {

// SingleSplitView lays out two views horizontally. A splitter exists between
// the two views that the user can drag around to resize the views.
class SingleSplitView : public views::View {
 public:
  enum Orientation {
    HORIZONTAL_SPLIT,
    VERTICAL_SPLIT
  };

  SingleSplitView(View* leading, View* trailing, Orientation orientation);

  virtual void DidChangeBounds(const gfx::Rect& previous,
                               const gfx::Rect& current);

  virtual void Layout();

  // SingleSplitView's preferred size is the sum of the preferred widths
  // and the max of the heights.
  virtual gfx::Size GetPreferredSize();

  // Overriden to return a resize cursor when over the divider.
  virtual gfx::NativeCursor GetCursorForPoint(Event::EventType event_type,
                                              int x,
                                              int y);

  void set_divider_offset(int divider_offset) {
    divider_offset_ = divider_offset;
  }
  int divider_offset() { return divider_offset_; }

  // Sets whether the leading component is resized when the split views size
  // changes. The default is true. A value of false results in the trailing
  // component resizing on a bounds change.
  void set_resize_leading_on_bounds_change(bool resize) {
    resize_leading_on_bounds_change_ = resize;
  }

 protected:
  virtual bool OnMousePressed(const MouseEvent& event);
  virtual bool OnMouseDragged(const MouseEvent& event);
  virtual void OnMouseReleased(const MouseEvent& event, bool canceled);

 private:
  // Returns true if |x| or |y| is over the divider.
  bool IsPointInDivider(int x, int y);

  // Returns width in case of horizontal split and height otherwise.
  int GetPrimaryAxisSize() {
    return GetPrimaryAxisSize(width(), height());
  }

  int GetPrimaryAxisSize(int h, int v) {
    return is_horizontal_ ? h : v;
  }

  // Used to track drag info.
  struct DragInfo {
    // The initial coordinate of the mouse when the user started the drag.
    int initial_mouse_offset;
    // The initial position of the divider when the user started the drag.
    int initial_divider_offset;
  };

  DragInfo drag_info_;

  // Orientation of the split view.
  bool is_horizontal_;

  // Position of the divider.
  int divider_offset_;

  bool resize_leading_on_bounds_change_;

  DISALLOW_COPY_AND_ASSIGN(SingleSplitView);
};

}  // namespace views

#endif  // VIEWS_CONTROLS_SINGLE_SPLIT_VIEW_H_